test: Remove unused imports

test/functional/wallet_listreceivedby.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# Copyright (c) 2014-2018 The Bitcoin Core developers
+# Copyright (c) 2014-2019 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test the listreceivedbyaddress RPC."""
@@ -10,7 +10,6 @@ from test_framework.util import (
     assert_array_result,
     assert_equal,
     assert_raises_rpc_error,
-    sync_blocks,
 )